Prototype modeling is a well known tool used during the design of model items and parts and components of complex systems. Typically, 3-Dimensional prototype models are used to test items and components prior to actual manufacture. Numerous 3-Dimensional model rapid prototyping methods are known. In particular, the method disclosed in U.S. Pat. No. 5,578,227 to Rabinovich, which is explicitly incorporated herein by reference, is particularly effective.
The steel rule die-cutting and die-making tools industry market amounts to about $6 billion worldwide. The industry provides services and die equipment to the converting industry markets, which include the producers of carton packaging boxes, automotive interior parts, gaskets, and tags and labels, to name a few. Packaging is an essential part of the American economy. About 90 percent of all products in this country are sold or moved through shipping cartons or corrugated boxes; from McDonald""s corrugated clamshells for its Big Mac sandwiches to Nike""s shoe boxes shipped around the world.
As reported by the Corrugated Packaging Council, the main association of the corrugated converting industry, the corrugated boxes converting industry segment is a $19 billion per year industry. That is the largest segment of the entire packaging industry. The State of the Industry report published in the March 1998 issue of Package Printing and Converting Magazine reports that, currently, the value of production for the North American folding carton-converting segment is about $6.8 billion. Added to this is an estimated $8 billion for the tags and labels segment. Those three segments of the converting industry constitute a $33.8 billion per year market, which is supported by the steel rule die making industry.
Small companies dominate the die-cutting and die-making industry. For generations they have been producing steel rule dies with methods that demand a high degree of craftsmanship and labor intensive operations.
Dies are called xe2x80x9csteel rule diesxe2x80x9d because the cutting and creasing blades resemble in height and thickness the width and thickness of steel rules. The following description details how steel rule dies are currently manufactured.
Sharpened and flat steel rule blades are bent and formed into a cutting and creasing pattern. The blades are held in position in a plywood, plastic, or metal die board. The die board is laser-grooved to accept and support the blades. In an operation called xe2x80x9cknifing,xe2x80x9d a skilled die maker manually inserts and secures the backs of thin pre-bent blades into the grooved die board. Sharp edge blades are used for cutting; creasing blades have rounded edges. The die maker then manually adjusts the height of the cutting and creasing blades by means of shims placed between the press and the back of the grooved die board holding the blades. The skilled die maker drives the die blades into the grooves in the die board by striking the sharpened cutting edges and rounded creasing edges with a plastic mallet. The die and the material to be cut are then placed in a press for the cutting operation.
With the increased automation on the converter""s side of the business, the demands for die accuracy and performance have been steadily increasing during the last two decades. Customer""s demands for greater die accuracy and performance are escalating. Those demands have forced many die-makers to purchase $350,000 groove-making laser systems and $120,000 automatic steel rule die bending machines to improve die accuracy and quality.
A finished die made with existing manufacturing methods requires labor intensive work, brings about slow customer delivery, and causes equipment down time due to loose rules falling out of the die board and consequent die re-ruling.
The main labor-intensive operations, such as the knifing of the die board and the knife""s height adjustment, are main contributors to increased die cost and slow customer delivery. For example, out of a total of forty-two (42) hours required for production of a benchmark die for fifty-two cigarette cartons, thirty (30) hours are spent on manual operations.
Therefore, a need exists for a more efficient and inexpensive method of producing steel rule dies. A need also exists, therefore, for a 3-Dimensional model rapid manufacturing method capable of generating 3-Dimensional models on flat and/or curved surfaces as a cylindrical or more complex 3-D surface used for a steel rule die base. The method may also generate corrugated structures, which may be used for speeding up steel rule build up. A need also exists for higher quality dies that are produced in shorter time frames and at reduced costs.
The improvements are achieved with the following additions to a basic solid feedstock deposition process described in U.S. Pat. No. 5,578,227 and application Ser. No. 08/755,214, which are hereby incorporated by reference.
An improvement is the addition of a means for continuous relative positioning of the feedstock deposition head and/or base so that feedstock is tangent to a base at the point of laser beam impeachment with the surface.
Other improvements are the provision of special feedstocks and the addition of V-shaped and rounded edges in feedstocks, which allow for the production of cutting and creasing blades used in steel rule die making, with or without additional milling or sharpening operations.
New steel rule die systems, processes, apparatus, and manufactured dies and feedstocks are presented by this invention.
A steel rule die is a cutting tool similar in form and function to a cookie cutter. There is an immediate opportunity to enter that market as an original equipment manufacturer (OEM) supplier of revolutionary steel rule die-making machines, process, and products.
A manufacturing process and system has been developed that is capable of automatically producing any 3-Dimensional steel rule die. The key element of this system is a Solid Feedstock Deposition (SFD) process, in which a solid flat feedstock of metal is laser fused, welded, brazed, or bonded onto a substrate and/or onto previously similarly fixed layers. This process and system is utilized in a steel rule die-making machine for an automatic direct deposition, fixing, and shaping of cutting and creasing blades.
The following description details how the new steel rule die-making machine works. The new steel rule in the form of a spooled flat wire is laser fused, welded, brazed, or bonded directly onto a die board, metal or nonmetal, and/or onto previous wire layers. Edges of outer layers are sharpened, triangular or rounded for cutting or creasing. Computer aided design and/or computer aided manufacturing (CAD/CAM) control the cutting and creasing patterns. The height of the steel rule die is controlled by the number of layers deposited. The machine sharpens the cutting areas of the die pattern. For many applications only a single pass of the wire is required. The entire process is fully automated. As is necessary in existing methods, the present invention requires no grooving of die boards, no separate rule bending, and no manual rule fitting into the grooves.
The present process and system bring revolutionary benefits to the steel rule die cutting industry by significantly reducing the die manufacturing costs, while improving die quality and expanding die capability.
The new steel rule die-making technology competes against established capital equipment manufacturers who supply equipment to the steel rule die-making industry for die board groove cutting and steel rule bending operations.
The new method of production of steel rule dies brings dramatic advantages in terms of production costs, quality, and customer response.
Another competing technology is the chemical etching approach used for the production of cutting dies. Although, chemical etching can produce cutting dies without the grooving and steel rule bending operations, chemical etching has a number of significant limitations that dramatically weakens their competitive position. That process produces a negative environmental impact. Chemical etching requires intensive disposal, treatment, and handling equipment that is extremely costly. The process is inherently slow. The chemical etching method is limited to processing of very thin materials, due to the limited rule height that is producible with that method.
The new steel rule dies, systems, manufacturing processes and machines, the resulting products, and the wires employed are features of the invention.
In the operations of the invention, the locating wire delivering bending, fixing, and sharpening head may move in X, Y, Z planar and arcuate directions and in rotation. The die plate holding and positioning table may similarly move. Movements of the head or table may be limited or interrelated. The die plate may be flat, cylindrical, undivided or segmental. In either case, the table may revolve or rotate and/or the head may revolve or rotate.
The present invention also provides for generating 3-Dimensional models that include layers of latticed feedstock. Layers of latticed feedstock may be used for the production of independent structural components or they may be used as filling techniques for internal cavities.
A model building apparatus includes a beam delivery module and a stage movable in the X, Y and Z directions. The model building apparatus dispenses feedstock, typically in the form of a thin strip of material such as stainless steel, onto a substrate. As used herein, substrate refers to the next, below or adjacent layer to which the feedstock is welded. The feedstock is formed into layers to construct a 3-Dimensional model. Each successive layer is fused to the immediately preceding layer until the complete model has been constructed. The present invention is a feedstock holding mechanism for a model building apparatus that enables the model building apparatus to corrugate the feedstock into a latticed layer. Generating 3-Dimensional models with latticed layers of corrugated feedstock significantly reduces the total amount of feedstock needed to make a given part.
The feedstock holding mechanism includes a feeder housing a spool of feedstock and jaws having push-down arms and side-holding arms. In operation, the substrate is fixed on the table, and the flat wire feedstock is held in the jaws while being spot welded or fused to the substrate by the beam delivery module, which may include a laser or electron beam or a plasma jet heating device of another energy source. The feedstock holding mechanism holds the feedstock to the substrate at its initial point of deposition, which improves the quality of the fusion at this point of first engagement of the feedstock with the substrate. After the initial point of the wire is fused, the jaws then release the feedstock and the stage moves horizontally away from the feeder thereby causing the material to be drawn from the feeder. The jaws are engaged and the table moves back toward the jaws, causing the feedstock to bend upward and downward, thereby corrugating the feedstock. The feedstock is then welded to the substrate at the endpoint of a corrugated wave. A top straight layer is then deposited. This process is repeated thereby forming a latticed layer of feedstock which is several times thicker than the thickness of the feedstock. Reducing the total number of layers that comprise the model significantly increases the speed of constructing models that do not require solid walls. During the above described process, the stage may be moved slightly downward and then upward during the away and return strokes to aid in the forming of the corrugation. Thus, the jaw and the feeder may move sequentially in the release, away, grip and back repetitive steps or in the away, up, grip, down and back repetitive steps. After each sequence of repetitive steps, the stage positions the substrate in a new position for the next weld. The size of the corrugation is controlled by controlling the length of the cyclic stroke.
The substrate 15 upon which the feedstock is deposited may be curved, such as cylindrical, or any free form 3-Dimensional substrate, in addition to being a flat plate. Rotary dies are used in many applications, such as cutting of labels, envelopes, flexible printed boards, and membrane switches. The production of rotary dies is much more complicated and expensive than the production of flat dies using current die manufacturing technologies, such as etching and hard tooling (machining of the cutting knives on cylindrical surfaces on a computer controlled milling machine). The present invention provides a significant reduction in the costs and time required to manufacture rotary dies.
These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings.